California’s System Operator has issued a $6.1bn transmission expansion plan

CAISO (California Independent System Operator) has announced a transmission expansion plan of 26 new projects to support the addition of 85GW of capacity by 2035, all to the tune of $6.1 billion.

CAISO’s 2023-2024 transmission plan recommends specific transmission upgrades based on reliability, policy and economic-driven concerns. Two of the projects recommended in the plan have been identified as eligible for competitive solicitation.

Specific projects recommended in this year’s plan, most notably to integrate offshore wind from the North Coast, include:

• A new Humboldt 500kV substation complete with a 500/115kV transformer;

• A new HVDC line (approximately 260 miles), initially operated as a 500kV AC line to interconnect the new Humboldt 500 kV substation to the Collinsville 500kV substation;

• A new 500kV AC line (approximately 140 miles) to interconnect new Humboldt 500kV substation to the Fern Road 500kV substation;

• A 115kV line from the new Humboldt 500kV line to existing Humboldt 115kV substation, and a 115kV phase-shifting transformer at the Humboldt 115 kV substation; and

• A host of smaller upgrades improving supply of load and access to other smaller resource zones.

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The transmission plan was developed in close coordination between CAISO and the California Energy Commission, the California Public Utilities Commission and the energy industry, and is hoped to enable critical resource development, including:

• Over 38GW of solar generation distributed across the state in solar development regions that include the Westlands area in the Central Valley, Tehachapi, the Kramer area in San Bernardino County, Riverside County, and also in southern Nevada and western Arizona;

• Over 3GW of in-state wind generation in existing wind development regions, including Tehachapi;

• Over 21GW of geothermal development, primarily in the Imperial Valley and in southern Nevada;

• Access for battery storage projects co-located across the state with renewable generation projects, as well as stand-alone storage located closer to major load centers in the LA Basin, greater Bay Area, and San Diego;

• The import of over 5.6GW of out-of-state wind generation from Idaho, Wyoming and New Mexico, by enhancing corridors from the ISO border in southeastern Nevada and from western Arizona into California load centers; and

• Over 4.7GW of offshore wind with 3.1GW in the Central Coast and 1.6GW in the North Coast area.

CAISO says they will continue to coordinate closely with regulators and industry in working through the timing and sequencing of offshore wind development to ensure reliability and affordability for electricity consumers.